Trunk closing = central locking?
I am a little bit confused on how the central locking works on my car. I have an 1998 M3 with the factory alarm/central locking. Recently I have noticed that sometimes after closing the trunk, the whole car will lock.(This does not happen every time I close the trunk, but it does rarely) I havent been able to pin point when it does it though. It has done this to me when the car was running and locked me out. That is why I am trying to figure out what is going on.
Does anybody know what causes the car to lock it self? Or what will cause it to do that?